Okay, so I'm trying to figure out what filters to use to get the same result as the Half-Life logo.

Here's the image for a reference:


What filters should I use?

This is my first post here, so I'm not sure if I'm in the right place to ask this.

You've posted this in the Tutorial and Resources section. The General Help section would have been a better place.
Also, https://krita-artists.org will have people who are more familiar with this sort of effect and so may be able to give useful advice.

It looks like grain/noise with maybe a bit of embossing.
You could try searching for those terms in the GMIC filters and see what they can do for you.